Viking 53' Convertible

I have a 95 Viking 54’ sport yacht (read MY). I have the 820s and my numbers are similar to yours. I run with a dinghy on the bow and usually atleast start out with full fuel and water is full. At 2050 I am right around 22 knots and burn 60 an hour with the genset running. I am propped conservatively as well. I cracked a case on one of the ZF 350s and ZF no longer makes them so I had both replaced with ZF 360s that come with a slightly lower gear ratio then the 350s so that has dropped my top end a touch. 27 knots is the best I will see. I am running 5 bladed Veems. I had my bottom blasted and re painted. I did not notice much difference. My experience thinks if you are reaching 2340 your bottom and running gear are pretty clean. I don’t think you will get much more than what you have. Mine won’t plane if it has barnacles on the wheels. Hope I am wrong but I don’t think you are far off. Others with more knowledge than me will respond.

Yes I do cruise at 2050. Boat seems to run better there. I am propped to reach 2400 fresh out of haul out. Wouldn’t surprise me if some experts think I am pushing to hard.

God only knows how.
With your engines, it's impossible to tell what the load is, at any given RPM.
The best you can get is an estimate, based on actual fuel burn.
But only as long as the boat has the equipment to measure it in real time, like the Floscan or Maretron flow sensors and instruments.
And you should reverse the logic, sort of: check the fuel burn first (which tells you how many hp the engine is producing), then compare it with the fuel burn at 100% load at the same RPM (as reported in MAN specs).
That's a half decent estimate of the load - anything else is just BS.

Just as an example, if your boat would run exactly along the theoretical propeller demand curve, at 2000 RPM your engines should burn 28 GPH each (with an output of 573hp). At the same RPM and full load, they would burn 38 GPH each instead (with an output of 785hp).
So, in this scenario, the engine load is 73% (calculated as either 28/36 or 573/785, which is the same, roundings aside).
But if the boat doesn't have any real time fuel burn measurement system, that surveyor could only make wild guesses, at any RPM.

Here is a picture of my pyrometer sensor (circled in red) and my pyro gauges(2 in the middle) that show my pyro temps. This is at cruise speed of approximately 2000 RPMs. Mapism in another thread recommended that I measure pyro temps from both banks of each engine. It would provide more info. I plan on doing this in the future. So think about that when you do yours.

Wow. If you are sure of that, you've got some cool running engines there.
Though as I recall, in CRM engines the much higher numbers quoted by Capt J are due to the fact that the probe is before, not after the turbo.

The suggestion of having the pyro on both banks is because it can allow an early diagnose of a faulty injector, in absence of any other reason why the readings shouldn't be consistent between each bank of the same engine.

PS: just curious, what is the plate under the e/r ceiling in the first pic above meant for?

I think the plate is a heat shield. Just saw CJ’s post. I am not a mechanic so I look to you guys/others for answers. The engines have always had that difference. So that is not new. Come to think of it the starboard may not have quite as high of max load RPM as indicated by the helm VDOs. Before I had the turbos blueprinted if my memory is right the starboard took longer than the port to reach WOT. As always I want the forums input. But I am not worried about it as a true expert just did the 1000hr and other things and he sea trialed the boat twice and said she was running as she should.

Here is a picture of the boost and pyro situation right after the turbos were blueprinted. The red marks were what it was before the turbos were blueprinted and the needles indicated what it was after they were blueprinted. I am not sure exactly what conclusions to draw from all of this but thought it might interest some of you.

Good deal on the increase in speed. I did not get those results when I stripped my bottom paint. I have been told that the 820s seem to run better in the 2000 - 2100 rpm range (if propped conservatively). My boat does seem to run better in the 2050 range. The pyro temps stay the same and it seems to not struggle as much getting over the backs of the waves in a following sea. If your turbos have not been blueprinted you would likely get some more performance improvement. I did. Less black smoke and stronger hole shoot. Don’t recall any significant increase in speed.